technetium-tc-99m-exametazime and Tuberous-Sclerosis

[Case records of Epileptic Disorders. Anatomo-electro clinical correlations. Case 01-2009]. Tuberous sclerosis complex (TSC) is a multisystem genetic disorder with variable phenotypic expression, caused by mutations in one of the two tumor suppressor genes, TSC1 or TSC2. Epilepsy is the most common neurological presentation and seizures are often medically intractable. Definition of the epileptogenic zone during presurgical evaluation is challenging given the multiple potentially epileptogenic lesions visible on MRI. However, TSC patients may nevertheless achieve seizure freedom, when preoperative evaluation yields concordant results. The strategies used in these patients vary substantially among different epilepsy surgery centres. We present a 21-year-old right-handed, intellectually not impaired woman with TSC and medically intractable seizures since the age of 15 years. Careful multi-stage presurgical evaluation, including prolonged video-EEG-monitoring, cerebral high resolution MRI, ictal and interictal [99m Tc]HMPAO-SPECT, [18 F]FDG-PET and further invasive recordings with subdural and depth electrodes led to the identification of an epileptogenic tuber with concordant seizure onset zone in the right neocortical temporal lobe. A tailored resection was performed leading to excellent surgical outcome (follow-up 12 months, Engel class I).

Topics: Age of Onset; Brain; Electroencephalography; Epilepsy; Female; Fluorodeoxyglucose F18; Humans; Magnetic Resonance Imaging; Neurosurgical Procedures; Positron-Emission Tomography; Radiopharmaceuticals; Technetium Tc 99m Exametazime; Temporal Lobe; Tomography, Emission-Computed, Single-Photon; Treatment Outcome; Tuberous Sclerosis; Young Adult

Although multiple cortical tubers are a hallmark of tuberous sclerosis complex (TSC), seizures often originate from a single tuber, making excisional surgery a therapeutic option for intractable patients. To assess the role of ictal single photon emission computed tomography (SPECT) in defining the epileptogenic tuber, we reviewed videoelectroencephalography (V/EEG) data, magnetic resonance imaging (MRI) and SPECT scans of 15 patients (aged 3 months to 15 years, mean 5.1) with medically resistant partial seizures and TSC. SPECT scans were performed using Tc-99m-hexamethylpropyleneamine oxime (HMPAO) injected within 30 seconds of electrographic seizure onset and were graded on a scale from 1 to 5 (1 weakly perfused, 5 strongly perfused). The scalp EEG revealed localized seizure origin in ten patients; five had concordant hyperperfused SPECT regions consisting of comma-shaped areas surrounding hypoperfused areas in the candidate tuber. Strongly hyperperfused regions (grade 3-5) were noted in two patients whose ictal EEG patterns were characterized by sustained, rhythmic fast activity or spiking. The other five patients had nonlocalizing or poorly sustained ictal EEG patterns; one patient in this group had focal hyperperfusion. Invasive EEG recordings in two patients revealed propagated EEG patterns that correlated with the ictal SPECT findings. These findings indicate a strong correlation between ictal SPECT and ictal scalp EEG, especially when there are sustained rhythmic fast ictal EEG patterns.

Topics: Adolescent; Brain Mapping; Cerebral Cortex; Child; Child, Preschool; Electroencephalography; Epilepsies, Partial; Epilepsy, Complex Partial; Female; Humans; Infant; Male; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tuberous Sclerosis; Video Recording

Tc-99m HMPAO was used to evaluate cerebral perfusion in a patient with tuberous sclerosis. The SPECT images demonstrated reduced HMPAO uptake in regions corresponding with MRI-confirmed locations of cortical tubers. These results indicate that the lesions are characterized by vascular perfusion deficits and support the hypothesis that cortical tubers result from developmental abnormalities of the embryonic central nervous system.

Topics: Brain; Cerebrovascular Circulation; Child; Humans; Magnetic Resonance Imaging; Male; Organotechnetium Compounds; Oximes; Technetium Tc 99m Exametazime; Tomography, Emission-Computed, Single-Photon; Tuberous Sclerosis